Re timing curves on the 123 system

[Ben Roberts]

Hello all. Great site.

I have a 123 distributor and noted a few forum members do too. There seem to be a number who use setting 8 rather than setting E on the programmable curves, however, I note at least in my 123 manual that the manufacturer suggest 8 is for 250SL's and E for 280SL's. For setting 8 max advance we have 2500 rpm/22 deg/crankshaft and for E 2500 rpm/20 deg crankshaft. This seems to be the basic difference. Anyone done a side by side on Euro SL's? Have mine set currently on E, with 8 deg BTDC idle, going to 38-40 BTDC at 3000 rpm advance (vac connected). No real issues other than that small timing adjustments to 123's require quite a bid of fiddling with the idle settings (at least in my hands). What might be the reason to go to setting 8?

Regards

Ben

Adelaide, South Australia, late 69 280SL, 904G, 906G

[BobH]

Hello Ben, you may have searched already for an answer, but if not use the search function above left for "123", quite a few posts on the subject, you may find what you're looking for, if not someone with experience may see your post and chime in

Bob

[stickandrudderman]

I'd be content to leave it where it is. 8 at idle and 38 at 3000 with vac is all you need to know.

[Bshaunessy]

Ben
  I installed a 123 distributor last Sept on 1970 280 SL auto, using factory recommend setting E.   very happy with performance so haven’t tried other settings. 
     Apparently 123 makes a blue tooth connected model that allows you to change operating curves from the cockpit while driving.  That would make your comparison between "curve 8” and "curve E" easy.    I did not opt for this option , preferring simple plug and play version.

[Pinder]

Just wondering for a 1970 SL with emissions and vacuum retard, if you use the 123 system do you bypass the vacuum controls and relays?

Regards

[dirkbalter]

Just wondering for a 1970 SL with emissions and vacuum retard, if you use the 123 system do you bypass the vacuum controls and relays?

Regards

I your emission system still works as designed, you can program the 123 (Bluetooth) accordingly. 

[Pinder]

It does work as far as my tests go but I feel is it really necessary to add all this extra complication when a new distributor that is as advanced as the 123. I like the principal of simplification to reduce points of failure. So what I am asking is if it is possible to not use vacuum advance at all but to program the 123 or have a setting that does not rely on the vacuum?

Regards


    Pinder

[Ben Roberts]

If it is of any use some of these issues are dealt with on their technical page: https://123ignitionusa.com/curve-tutorial/
I suppose on the Bluetooth version you can theoretically program whatever you want if you know how to relate it to the engine variants, but then you would still need to physically check it all with the strobe. On my "simple" 123 I'll currently run with setting "E" in the absence of any compelling technical information to switch. 

Ben


 

[dirkbalter]

It does work as far as my tests go but I feel is it really necessary to add all this extra complication when a new distributor that is as advanced as the 123. I like the principal of simplification to reduce points of failure. So what I am asking is if it is possible to not use vacuum advance at all but to program the 123 or have a setting that does not rely on the vacuum?

Regards


    Pinder

Well, I cant really give you an educated answer here. In a typical setup, if you go off the gas, the throttle body will close and max vacuum is generated, affecting the timing somewhat instantly.  If you rely strictly on the engine rpm to change the timing, the curve is different and it may not have the same effect or the performance you are looking for.
Others may know more.
   

[Chris Long]

Yes - buy the bluethtooth version and can be setup; mine is setup this way and a number of others.

[Pinder]

Thanks Chris

   So where did you order yours from? I think the one I see on Vintage Euro Parts website is not the bluetooth version.

Regards

 Pinder

[dirkbalter]

Thanks Chris

   So where did you order yours from? I think the one I see on Vintage Euro Parts website is not the bluetooth version.

Regards

 Pinder

I have and would buy direct from 123. They have good support as well should you need it.
https://123ignitionusa.com/

[Pinder]

Thank you Dirk.

Much appreciated.

Regards

  Pinder

[Pinder]

for the Switched version, which model do I need.

is it  Sku: Merc 6-R-V-IE     or  Sku: Merc 6-R-V

I think its  Sku: Merc 6-R-V but I am not sure.

[dirkbalter]

Pinder,
I would think it depends on what you are trying to accomplish. The switch version is fine if you just want to mimic a regular (051 for example) distributor.  On my 70 280, the emissions relays did not work any more an I chose to go for the programmable one to have more flexibility. I ended up also changing the throttle body but according the Chris Long above, it can be successfully programmed to work without vacuum input.
But don't take my word for it. I found Ed Madak from 123 very helpful and would give him a call to confirm your theories.
Hope that helps.

[bracurrie]

The IE is for cars with electronic injection systems.
I am looking at the TUNE+-6-R-V-M so I can adjust on the fly if needed for less than ideal fuel. I want to use maximum advance and with the non-ethanol 93 octane I have available I can run factory timing spec with no issues. But if I travel I may have to settle for lower octane fuel with ethanol, so I want to be able to retard the curve a few degrees to avoid pinging.
On the issue of the vacuum retardation for emissions. I have disabled mine because it didn't work properly. The only thing I wish to get is a vacuum advance style throttle body to get the advantages of advancement under load and retardation during de-acceleration which would save some gas. 

[Pinder]

I placed my order for the blue tooth version  just so I have the flexibility if needed to make any adjustments. I plan to run it with the vacuum / emissions as is on the 1970 280SL.  If that works Ok I will leave it like that. If not I have modified my  throttle body with the vacuum hole drilled in and I copied the location from the 1969 that I sold last year I have it capped off for now but having it just gives some flexability and I dont need to buy an older throttle body.  I can play around with both options and see what runs best.

 Thanks for everyone's input.

[Pinder]

Part way into the install of the 123 Ignition. What’s the consensus on the spring? Leave it in or take it out? Or replace with longer one?

Regards

 Pinder

[Jonny B]

I can add one point of experience. We put the spring supplied with the unit in place. No issues so far, unit installed October 2022.

[Pinder]

Thanks Johnny. Mine  did not come with the spring. I contacted Ed Madal from 123ignition USA and he said to leave the spring . Maybe with latest version it’s not needed?

Regards

Pinder

[Pinder]

I have the system installed and running.  Currently i have it without any vacuum retard. (MAP which i disabled from the App).

Its running pretty good with mechanical advance option set as below.

rpm BTDC
500 4.0
1000 8.0
3000 38.0
3000+38.0

[Pinder]

I now have the vacuum line hooked up from throttle body directly to the distrib. I am using the port that should work like the older vaccum advance setup so that vaccum is highest at idle and drops off as the throttle plate opens.

Does anyone have a map curve and advance cuve that I can try? I think what I need is setting 8 for the switchable 123 . I have the time version blue tooth.

Regards

[Pinder]

Added the map curve and  timing curve  to simulate the 051 distrib  using 123 ignition Bluetooth. This seems to work fine for my setup.